The entrance of air into and the passage of air through the interior of an aircraft during flight is known to have an adverse affect on performance. The flow of air into the interior cavities of an aircraft creates a loss in the momentum of the local airflow over the wing and consequently increases drag. Openings in the air craft may stem from an imperfect seal between various components, such as between the fuselage and the landing cavity doors, between the forward edge of the fixed wing and forward slats or between the rearward edge portion of the fixed wing and various flaps or spoilers. Openings that lie in higher pressure regions of the aircraft act as air inlets while the openings in lower pressure regions act as air outlets.
In the past, attempts have been made to reduce internal airflow by using seals to minimize the size of openings in the aircraft. Resilient, bulb-type seals have been placed around the inside perimeter of forward slats to press against the forward edge portion of the fixed wing to decrease the airflow through the coves existing between the slats and the fixed wing. Bulb seals also have been placed between the abutting end portions of adjacent wing flaps to block the passage of air therebetween. In addition, seals have been positioned around the perimeter of ailerons to prevent air leakage into the aileron cavity and the adjacent portions of the wing. While these seals may help to control the volume of air entering the interior of an aircraft, they are not entirely effective, in part due to deflections in the flaps and other components during flight and due to changes in the resiliency of the seal material with variations in ambient conditions. Moreover, these seals do not address the problem of blocking airflow once the air has actually gained entrance into the aircraft by flowing past the seals or through drain holes formed in various portions of the wing to expel moisture that has accumulated therein.
Also, in the past, large components or cavities of an aircraft have been sealed from each other. For instance, the cavity that houses aircraft landing gear has been divided from adjacent portions of the fuselage and the inboard end of the wing by use of rather large partitions that could substantially increase the weight of the aircraft. It can be appreciated that indiscriminate use of such partitions may negatively affect performance by increasing the weight of the aircraft beyond the efficiencies achieved by reduction in drag. Moreover, the partitions placed between the component sections of the aircraft do not adequately address the problem of reducing internal airflow through various portions of individual cavities themselves, such as through the rear spar cavity of a wing.
Accordingly, it is a principal object of the present invention to decrease the drag on an aircraft by blocking the flow of air through the interior of the aircraft wing, and especially through the rear spar cavity of the wing.
It is a particular object of this invention to strategically locate air dams within an aircraft wing to achieve a high level of drag reduction relative to the increase in the weight of the aircraft from the presence of air dams.
It is another particular object of this invention to incorporate the air dams into structural, load-bearing components of the wing.